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Btrfs: optimize btrget/set/removexattr
[deliverable/linux.git] / fs / btrfs / file.c
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/fs.h>
20 #include <linux/pagemap.h>
21 #include <linux/highmem.h>
22 #include <linux/time.h>
23 #include <linux/init.h>
24 #include <linux/string.h>
25 #include <linux/smp_lock.h>
26 #include <linux/backing-dev.h>
27 #include <linux/mpage.h>
28 #include <linux/swap.h>
29 #include <linux/writeback.h>
30 #include <linux/statfs.h>
31 #include <linux/compat.h>
32 #include <linux/version.h>
33 #include "ctree.h"
34 #include "disk-io.h"
35 #include "transaction.h"
36 #include "btrfs_inode.h"
37 #include "ioctl.h"
38 #include "print-tree.h"
39 #include "compat.h"
40
41
42 static int btrfs_copy_from_user(loff_t pos, int num_pages, int write_bytes,
43 struct page **prepared_pages,
44 const char __user * buf)
45 {
46 long page_fault = 0;
47 int i;
48 int offset = pos & (PAGE_CACHE_SIZE - 1);
49
50 for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
51 size_t count = min_t(size_t,
52 PAGE_CACHE_SIZE - offset, write_bytes);
53 struct page *page = prepared_pages[i];
54 fault_in_pages_readable(buf, count);
55
56 /* Copy data from userspace to the current page */
57 kmap(page);
58 page_fault = __copy_from_user(page_address(page) + offset,
59 buf, count);
60 /* Flush processor's dcache for this page */
61 flush_dcache_page(page);
62 kunmap(page);
63 buf += count;
64 write_bytes -= count;
65
66 if (page_fault)
67 break;
68 }
69 return page_fault ? -EFAULT : 0;
70 }
71
72 static void btrfs_drop_pages(struct page **pages, size_t num_pages)
73 {
74 size_t i;
75 for (i = 0; i < num_pages; i++) {
76 if (!pages[i])
77 break;
78 ClearPageChecked(pages[i]);
79 unlock_page(pages[i]);
80 mark_page_accessed(pages[i]);
81 page_cache_release(pages[i]);
82 }
83 }
84
85 static int noinline insert_inline_extent(struct btrfs_trans_handle *trans,
86 struct btrfs_root *root, struct inode *inode,
87 u64 offset, size_t size,
88 struct page **pages, size_t page_offset,
89 int num_pages)
90 {
91 struct btrfs_key key;
92 struct btrfs_path *path;
93 struct extent_buffer *leaf;
94 char *kaddr;
95 unsigned long ptr;
96 struct btrfs_file_extent_item *ei;
97 struct page *page;
98 u32 datasize;
99 int err = 0;
100 int ret;
101 int i;
102 ssize_t cur_size;
103
104 path = btrfs_alloc_path();
105 if (!path)
106 return -ENOMEM;
107
108 btrfs_set_trans_block_group(trans, inode);
109
110 key.objectid = inode->i_ino;
111 key.offset = offset;
112 btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
113
114 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
115 if (ret < 0) {
116 err = ret;
117 goto fail;
118 }
119 if (ret == 1) {
120 struct btrfs_key found_key;
121
122 if (path->slots[0] == 0)
123 goto insert;
124
125 path->slots[0]--;
126 leaf = path->nodes[0];
127 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
128
129 if (found_key.objectid != inode->i_ino)
130 goto insert;
131
132 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
133 goto insert;
134 ei = btrfs_item_ptr(leaf, path->slots[0],
135 struct btrfs_file_extent_item);
136
137 if (btrfs_file_extent_type(leaf, ei) !=
138 BTRFS_FILE_EXTENT_INLINE) {
139 goto insert;
140 }
141 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
142 ret = 0;
143 }
144 if (ret == 0) {
145 u32 found_size;
146 u64 found_end;
147
148 leaf = path->nodes[0];
149 ei = btrfs_item_ptr(leaf, path->slots[0],
150 struct btrfs_file_extent_item);
151
152 if (btrfs_file_extent_type(leaf, ei) !=
153 BTRFS_FILE_EXTENT_INLINE) {
154 err = ret;
155 btrfs_print_leaf(root, leaf);
156 printk("found wasn't inline offset %Lu inode %lu\n",
157 offset, inode->i_ino);
158 goto fail;
159 }
160 found_size = btrfs_file_extent_inline_len(leaf,
161 btrfs_item_nr(leaf, path->slots[0]));
162 found_end = key.offset + found_size;
163
164 if (found_end < offset + size) {
165 btrfs_release_path(root, path);
166 ret = btrfs_search_slot(trans, root, &key, path,
167 offset + size - found_end, 1);
168 BUG_ON(ret != 0);
169
170 ret = btrfs_extend_item(trans, root, path,
171 offset + size - found_end);
172 if (ret) {
173 err = ret;
174 goto fail;
175 }
176 leaf = path->nodes[0];
177 ei = btrfs_item_ptr(leaf, path->slots[0],
178 struct btrfs_file_extent_item);
179 inode->i_blocks += (offset + size - found_end) >> 9;
180 }
181 if (found_end < offset) {
182 ptr = btrfs_file_extent_inline_start(ei) + found_size;
183 memset_extent_buffer(leaf, 0, ptr, offset - found_end);
184 }
185 } else {
186 insert:
187 btrfs_release_path(root, path);
188 datasize = offset + size - key.offset;
189 inode->i_blocks += datasize >> 9;
190 datasize = btrfs_file_extent_calc_inline_size(datasize);
191 ret = btrfs_insert_empty_item(trans, root, path, &key,
192 datasize);
193 if (ret) {
194 err = ret;
195 printk("got bad ret %d\n", ret);
196 goto fail;
197 }
198 leaf = path->nodes[0];
199 ei = btrfs_item_ptr(leaf, path->slots[0],
200 struct btrfs_file_extent_item);
201 btrfs_set_file_extent_generation(leaf, ei, trans->transid);
202 btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
203 }
204 ptr = btrfs_file_extent_inline_start(ei) + offset - key.offset;
205
206 cur_size = size;
207 i = 0;
208 while (size > 0) {
209 page = pages[i];
210 kaddr = kmap_atomic(page, KM_USER0);
211 cur_size = min_t(size_t, PAGE_CACHE_SIZE - page_offset, size);
212 write_extent_buffer(leaf, kaddr + page_offset, ptr, cur_size);
213 kunmap_atomic(kaddr, KM_USER0);
214 page_offset = 0;
215 ptr += cur_size;
216 size -= cur_size;
217 if (i >= num_pages) {
218 printk("i %d num_pages %d\n", i, num_pages);
219 }
220 i++;
221 }
222 btrfs_mark_buffer_dirty(leaf);
223 fail:
224 btrfs_free_path(path);
225 return err;
226 }
227
228 static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
229 struct btrfs_root *root,
230 struct file *file,
231 struct page **pages,
232 size_t num_pages,
233 loff_t pos,
234 size_t write_bytes)
235 {
236 int err = 0;
237 int i;
238 struct inode *inode = fdentry(file)->d_inode;
239 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
240 u64 hint_byte;
241 u64 num_bytes;
242 u64 start_pos;
243 u64 end_of_last_block;
244 u64 end_pos = pos + write_bytes;
245 u64 inline_size;
246 int did_inline = 0;
247 loff_t isize = i_size_read(inode);
248
249 start_pos = pos & ~((u64)root->sectorsize - 1);
250 num_bytes = (write_bytes + pos - start_pos +
251 root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
252
253 end_of_last_block = start_pos + num_bytes - 1;
254
255 lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
256 trans = btrfs_join_transaction(root, 1);
257 if (!trans) {
258 err = -ENOMEM;
259 goto out_unlock;
260 }
261 btrfs_set_trans_block_group(trans, inode);
262 hint_byte = 0;
263
264 if ((end_of_last_block & 4095) == 0) {
265 printk("strange end of last %Lu %zu %Lu\n", start_pos, write_bytes, end_of_last_block);
266 }
267 set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
268
269 /* FIXME...EIEIO, ENOSPC and more */
270 /* insert any holes we need to create */
271 if (isize < start_pos) {
272 u64 last_pos_in_file;
273 u64 hole_size;
274 u64 mask = root->sectorsize - 1;
275 last_pos_in_file = (isize + mask) & ~mask;
276 hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
277 if (hole_size > 0) {
278 btrfs_wait_ordered_range(inode, last_pos_in_file,
279 last_pos_in_file + hole_size);
280 mutex_lock(&BTRFS_I(inode)->extent_mutex);
281 err = btrfs_drop_extents(trans, root, inode,
282 last_pos_in_file,
283 last_pos_in_file + hole_size,
284 last_pos_in_file,
285 &hint_byte);
286 if (err)
287 goto failed;
288
289 err = btrfs_insert_file_extent(trans, root,
290 inode->i_ino,
291 last_pos_in_file,
292 0, 0, hole_size, 0);
293 btrfs_drop_extent_cache(inode, last_pos_in_file,
294 last_pos_in_file + hole_size -1);
295 mutex_unlock(&BTRFS_I(inode)->extent_mutex);
296 btrfs_check_file(root, inode);
297 }
298 if (err)
299 goto failed;
300 }
301
302 /*
303 * either allocate an extent for the new bytes or setup the key
304 * to show we are doing inline data in the extent
305 */
306 inline_size = end_pos;
307 if (isize >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
308 inline_size > root->fs_info->max_inline ||
309 (inline_size & (root->sectorsize -1)) == 0 ||
310 inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root)) {
311 /* check for reserved extents on each page, we don't want
312 * to reset the delalloc bit on things that already have
313 * extents reserved.
314 */
315 btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
316 for (i = 0; i < num_pages; i++) {
317 struct page *p = pages[i];
318 SetPageUptodate(p);
319 ClearPageChecked(p);
320 set_page_dirty(p);
321 }
322 } else {
323 u64 aligned_end;
324 /* step one, delete the existing extents in this range */
325 aligned_end = (pos + write_bytes + root->sectorsize - 1) &
326 ~((u64)root->sectorsize - 1);
327 mutex_lock(&BTRFS_I(inode)->extent_mutex);
328 err = btrfs_drop_extents(trans, root, inode, start_pos,
329 aligned_end, aligned_end, &hint_byte);
330 if (err)
331 goto failed;
332 if (isize > inline_size)
333 inline_size = min_t(u64, isize, aligned_end);
334 inline_size -= start_pos;
335 err = insert_inline_extent(trans, root, inode, start_pos,
336 inline_size, pages, 0, num_pages);
337 btrfs_drop_extent_cache(inode, start_pos, aligned_end - 1);
338 BUG_ON(err);
339 mutex_unlock(&BTRFS_I(inode)->extent_mutex);
340
341 /*
342 * an ugly way to do all the prop accounting around
343 * the page bits and mapping tags
344 */
345 set_page_writeback(pages[0]);
346 end_page_writeback(pages[0]);
347 did_inline = 1;
348 }
349 if (end_pos > isize) {
350 i_size_write(inode, end_pos);
351 if (did_inline)
352 BTRFS_I(inode)->disk_i_size = end_pos;
353 btrfs_update_inode(trans, root, inode);
354 }
355 failed:
356 err = btrfs_end_transaction(trans, root);
357 out_unlock:
358 unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
359 return err;
360 }
361
362 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
363 {
364 struct extent_map *em;
365 struct extent_map *split = NULL;
366 struct extent_map *split2 = NULL;
367 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
368 u64 len = end - start + 1;
369 int ret;
370 int testend = 1;
371
372 WARN_ON(end < start);
373 if (end == (u64)-1) {
374 len = (u64)-1;
375 testend = 0;
376 }
377 while(1) {
378 if (!split)
379 split = alloc_extent_map(GFP_NOFS);
380 if (!split2)
381 split2 = alloc_extent_map(GFP_NOFS);
382
383 spin_lock(&em_tree->lock);
384 em = lookup_extent_mapping(em_tree, start, len);
385 if (!em) {
386 spin_unlock(&em_tree->lock);
387 break;
388 }
389 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
390 remove_extent_mapping(em_tree, em);
391
392 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
393 em->start < start) {
394 split->start = em->start;
395 split->len = start - em->start;
396 split->block_start = em->block_start;
397 split->bdev = em->bdev;
398 split->flags = em->flags;
399 ret = add_extent_mapping(em_tree, split);
400 BUG_ON(ret);
401 free_extent_map(split);
402 split = split2;
403 split2 = NULL;
404 }
405 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
406 testend && em->start + em->len > start + len) {
407 u64 diff = start + len - em->start;
408
409 split->start = start + len;
410 split->len = em->start + em->len - (start + len);
411 split->bdev = em->bdev;
412 split->flags = em->flags;
413
414 split->block_start = em->block_start + diff;
415
416 ret = add_extent_mapping(em_tree, split);
417 BUG_ON(ret);
418 free_extent_map(split);
419 split = NULL;
420 }
421 spin_unlock(&em_tree->lock);
422
423 /* once for us */
424 free_extent_map(em);
425 /* once for the tree*/
426 free_extent_map(em);
427 }
428 if (split)
429 free_extent_map(split);
430 if (split2)
431 free_extent_map(split2);
432 return 0;
433 }
434
435 int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
436 {
437 return 0;
438 #if 0
439 struct btrfs_path *path;
440 struct btrfs_key found_key;
441 struct extent_buffer *leaf;
442 struct btrfs_file_extent_item *extent;
443 u64 last_offset = 0;
444 int nritems;
445 int slot;
446 int found_type;
447 int ret;
448 int err = 0;
449 u64 extent_end = 0;
450
451 path = btrfs_alloc_path();
452 ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
453 last_offset, 0);
454 while(1) {
455 nritems = btrfs_header_nritems(path->nodes[0]);
456 if (path->slots[0] >= nritems) {
457 ret = btrfs_next_leaf(root, path);
458 if (ret)
459 goto out;
460 nritems = btrfs_header_nritems(path->nodes[0]);
461 }
462 slot = path->slots[0];
463 leaf = path->nodes[0];
464 btrfs_item_key_to_cpu(leaf, &found_key, slot);
465 if (found_key.objectid != inode->i_ino)
466 break;
467 if (found_key.type != BTRFS_EXTENT_DATA_KEY)
468 goto out;
469
470 if (found_key.offset < last_offset) {
471 WARN_ON(1);
472 btrfs_print_leaf(root, leaf);
473 printk("inode %lu found offset %Lu expected %Lu\n",
474 inode->i_ino, found_key.offset, last_offset);
475 err = 1;
476 goto out;
477 }
478 extent = btrfs_item_ptr(leaf, slot,
479 struct btrfs_file_extent_item);
480 found_type = btrfs_file_extent_type(leaf, extent);
481 if (found_type == BTRFS_FILE_EXTENT_REG) {
482 extent_end = found_key.offset +
483 btrfs_file_extent_num_bytes(leaf, extent);
484 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
485 struct btrfs_item *item;
486 item = btrfs_item_nr(leaf, slot);
487 extent_end = found_key.offset +
488 btrfs_file_extent_inline_len(leaf, item);
489 extent_end = (extent_end + root->sectorsize - 1) &
490 ~((u64)root->sectorsize -1 );
491 }
492 last_offset = extent_end;
493 path->slots[0]++;
494 }
495 if (0 && last_offset < inode->i_size) {
496 WARN_ON(1);
497 btrfs_print_leaf(root, leaf);
498 printk("inode %lu found offset %Lu size %Lu\n", inode->i_ino,
499 last_offset, inode->i_size);
500 err = 1;
501
502 }
503 out:
504 btrfs_free_path(path);
505 return err;
506 #endif
507 }
508
509 /*
510 * this is very complex, but the basic idea is to drop all extents
511 * in the range start - end. hint_block is filled in with a block number
512 * that would be a good hint to the block allocator for this file.
513 *
514 * If an extent intersects the range but is not entirely inside the range
515 * it is either truncated or split. Anything entirely inside the range
516 * is deleted from the tree.
517 */
518 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
519 struct btrfs_root *root, struct inode *inode,
520 u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
521 {
522 u64 extent_end = 0;
523 u64 search_start = start;
524 struct extent_buffer *leaf;
525 struct btrfs_file_extent_item *extent;
526 struct btrfs_path *path;
527 struct btrfs_key key;
528 struct btrfs_file_extent_item old;
529 int keep;
530 int slot;
531 int bookend;
532 int found_type;
533 int found_extent;
534 int found_inline;
535 int recow;
536 int ret;
537
538 btrfs_drop_extent_cache(inode, start, end - 1);
539
540 path = btrfs_alloc_path();
541 if (!path)
542 return -ENOMEM;
543 while(1) {
544 recow = 0;
545 btrfs_release_path(root, path);
546 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
547 search_start, -1);
548 if (ret < 0)
549 goto out;
550 if (ret > 0) {
551 if (path->slots[0] == 0) {
552 ret = 0;
553 goto out;
554 }
555 path->slots[0]--;
556 }
557 next_slot:
558 keep = 0;
559 bookend = 0;
560 found_extent = 0;
561 found_inline = 0;
562 extent = NULL;
563 leaf = path->nodes[0];
564 slot = path->slots[0];
565 ret = 0;
566 btrfs_item_key_to_cpu(leaf, &key, slot);
567 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
568 key.offset >= end) {
569 goto out;
570 }
571 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
572 key.objectid != inode->i_ino) {
573 goto out;
574 }
575 if (recow) {
576 search_start = key.offset;
577 continue;
578 }
579 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
580 extent = btrfs_item_ptr(leaf, slot,
581 struct btrfs_file_extent_item);
582 found_type = btrfs_file_extent_type(leaf, extent);
583 if (found_type == BTRFS_FILE_EXTENT_REG) {
584 extent_end =
585 btrfs_file_extent_disk_bytenr(leaf,
586 extent);
587 if (extent_end)
588 *hint_byte = extent_end;
589
590 extent_end = key.offset +
591 btrfs_file_extent_num_bytes(leaf, extent);
592 found_extent = 1;
593 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
594 struct btrfs_item *item;
595 item = btrfs_item_nr(leaf, slot);
596 found_inline = 1;
597 extent_end = key.offset +
598 btrfs_file_extent_inline_len(leaf, item);
599 }
600 } else {
601 extent_end = search_start;
602 }
603
604 /* we found nothing we can drop */
605 if ((!found_extent && !found_inline) ||
606 search_start >= extent_end) {
607 int nextret;
608 u32 nritems;
609 nritems = btrfs_header_nritems(leaf);
610 if (slot >= nritems - 1) {
611 nextret = btrfs_next_leaf(root, path);
612 if (nextret)
613 goto out;
614 recow = 1;
615 } else {
616 path->slots[0]++;
617 }
618 goto next_slot;
619 }
620
621 if (found_inline) {
622 u64 mask = root->sectorsize - 1;
623 search_start = (extent_end + mask) & ~mask;
624 } else
625 search_start = extent_end;
626 if (end <= extent_end && start >= key.offset && found_inline) {
627 *hint_byte = EXTENT_MAP_INLINE;
628 continue;
629 }
630 if (end < extent_end && end >= key.offset) {
631 if (found_extent) {
632 u64 disk_bytenr =
633 btrfs_file_extent_disk_bytenr(leaf, extent);
634 u64 disk_num_bytes =
635 btrfs_file_extent_disk_num_bytes(leaf,
636 extent);
637 read_extent_buffer(leaf, &old,
638 (unsigned long)extent,
639 sizeof(old));
640 if (disk_bytenr != 0) {
641 ret = btrfs_inc_extent_ref(trans, root,
642 disk_bytenr, disk_num_bytes,
643 root->root_key.objectid,
644 trans->transid,
645 key.objectid, end);
646 BUG_ON(ret);
647 }
648 }
649 bookend = 1;
650 if (found_inline && start <= key.offset)
651 keep = 1;
652 }
653 /* truncate existing extent */
654 if (start > key.offset) {
655 u64 new_num;
656 u64 old_num;
657 keep = 1;
658 WARN_ON(start & (root->sectorsize - 1));
659 if (found_extent) {
660 new_num = start - key.offset;
661 old_num = btrfs_file_extent_num_bytes(leaf,
662 extent);
663 *hint_byte =
664 btrfs_file_extent_disk_bytenr(leaf,
665 extent);
666 if (btrfs_file_extent_disk_bytenr(leaf,
667 extent)) {
668 dec_i_blocks(inode, old_num - new_num);
669 }
670 btrfs_set_file_extent_num_bytes(leaf, extent,
671 new_num);
672 btrfs_mark_buffer_dirty(leaf);
673 } else if (key.offset < inline_limit &&
674 (end > extent_end) &&
675 (inline_limit < extent_end)) {
676 u32 new_size;
677 new_size = btrfs_file_extent_calc_inline_size(
678 inline_limit - key.offset);
679 dec_i_blocks(inode, (extent_end - key.offset) -
680 (inline_limit - key.offset));
681 btrfs_truncate_item(trans, root, path,
682 new_size, 1);
683 }
684 }
685 /* delete the entire extent */
686 if (!keep) {
687 u64 disk_bytenr = 0;
688 u64 disk_num_bytes = 0;
689 u64 extent_num_bytes = 0;
690 u64 root_gen;
691 u64 root_owner;
692
693 root_gen = btrfs_header_generation(leaf);
694 root_owner = btrfs_header_owner(leaf);
695 if (found_extent) {
696 disk_bytenr =
697 btrfs_file_extent_disk_bytenr(leaf,
698 extent);
699 disk_num_bytes =
700 btrfs_file_extent_disk_num_bytes(leaf,
701 extent);
702 extent_num_bytes =
703 btrfs_file_extent_num_bytes(leaf, extent);
704 *hint_byte =
705 btrfs_file_extent_disk_bytenr(leaf,
706 extent);
707 }
708 ret = btrfs_del_item(trans, root, path);
709 /* TODO update progress marker and return */
710 BUG_ON(ret);
711 btrfs_release_path(root, path);
712 extent = NULL;
713 if (found_extent && disk_bytenr != 0) {
714 dec_i_blocks(inode, extent_num_bytes);
715 ret = btrfs_free_extent(trans, root,
716 disk_bytenr,
717 disk_num_bytes,
718 root_owner,
719 root_gen, inode->i_ino,
720 key.offset, 0);
721 }
722
723 BUG_ON(ret);
724 if (!bookend && search_start >= end) {
725 ret = 0;
726 goto out;
727 }
728 if (!bookend)
729 continue;
730 }
731 if (bookend && found_inline && start <= key.offset) {
732 u32 new_size;
733 new_size = btrfs_file_extent_calc_inline_size(
734 extent_end - end);
735 dec_i_blocks(inode, (extent_end - key.offset) -
736 (extent_end - end));
737 btrfs_truncate_item(trans, root, path, new_size, 0);
738 }
739 /* create bookend, splitting the extent in two */
740 if (bookend && found_extent) {
741 struct btrfs_key ins;
742 ins.objectid = inode->i_ino;
743 ins.offset = end;
744 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
745 btrfs_release_path(root, path);
746 ret = btrfs_insert_empty_item(trans, root, path, &ins,
747 sizeof(*extent));
748
749 leaf = path->nodes[0];
750 if (ret) {
751 btrfs_print_leaf(root, leaf);
752 printk("got %d on inserting %Lu %u %Lu start %Lu end %Lu found %Lu %Lu keep was %d\n", ret , ins.objectid, ins.type, ins.offset, start, end, key.offset, extent_end, keep);
753 }
754 BUG_ON(ret);
755 extent = btrfs_item_ptr(leaf, path->slots[0],
756 struct btrfs_file_extent_item);
757 write_extent_buffer(leaf, &old,
758 (unsigned long)extent, sizeof(old));
759
760 btrfs_set_file_extent_offset(leaf, extent,
761 le64_to_cpu(old.offset) + end - key.offset);
762 WARN_ON(le64_to_cpu(old.num_bytes) <
763 (extent_end - end));
764 btrfs_set_file_extent_num_bytes(leaf, extent,
765 extent_end - end);
766 btrfs_set_file_extent_type(leaf, extent,
767 BTRFS_FILE_EXTENT_REG);
768
769 btrfs_mark_buffer_dirty(path->nodes[0]);
770 if (le64_to_cpu(old.disk_bytenr) != 0) {
771 inode->i_blocks +=
772 btrfs_file_extent_num_bytes(leaf,
773 extent) >> 9;
774 }
775 ret = 0;
776 goto out;
777 }
778 }
779 out:
780 btrfs_free_path(path);
781 btrfs_check_file(root, inode);
782 return ret;
783 }
784
785 /*
786 * this gets pages into the page cache and locks them down
787 */
788 static int prepare_pages(struct btrfs_root *root, struct file *file,
789 struct page **pages, size_t num_pages,
790 loff_t pos, unsigned long first_index,
791 unsigned long last_index, size_t write_bytes)
792 {
793 int i;
794 unsigned long index = pos >> PAGE_CACHE_SHIFT;
795 struct inode *inode = fdentry(file)->d_inode;
796 int err = 0;
797 u64 start_pos;
798 u64 last_pos;
799
800 start_pos = pos & ~((u64)root->sectorsize - 1);
801 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
802
803 memset(pages, 0, num_pages * sizeof(struct page *));
804 again:
805 for (i = 0; i < num_pages; i++) {
806 pages[i] = grab_cache_page(inode->i_mapping, index + i);
807 if (!pages[i]) {
808 err = -ENOMEM;
809 BUG_ON(1);
810 }
811 wait_on_page_writeback(pages[i]);
812 }
813 if (start_pos < inode->i_size) {
814 struct btrfs_ordered_extent *ordered;
815 lock_extent(&BTRFS_I(inode)->io_tree,
816 start_pos, last_pos - 1, GFP_NOFS);
817 ordered = btrfs_lookup_first_ordered_extent(inode, last_pos -1);
818 if (ordered &&
819 ordered->file_offset + ordered->len > start_pos &&
820 ordered->file_offset < last_pos) {
821 btrfs_put_ordered_extent(ordered);
822 unlock_extent(&BTRFS_I(inode)->io_tree,
823 start_pos, last_pos - 1, GFP_NOFS);
824 for (i = 0; i < num_pages; i++) {
825 unlock_page(pages[i]);
826 page_cache_release(pages[i]);
827 }
828 btrfs_wait_ordered_range(inode, start_pos,
829 last_pos - start_pos);
830 goto again;
831 }
832 if (ordered)
833 btrfs_put_ordered_extent(ordered);
834
835 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
836 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
837 GFP_NOFS);
838 unlock_extent(&BTRFS_I(inode)->io_tree,
839 start_pos, last_pos - 1, GFP_NOFS);
840 }
841 for (i = 0; i < num_pages; i++) {
842 clear_page_dirty_for_io(pages[i]);
843 set_page_extent_mapped(pages[i]);
844 WARN_ON(!PageLocked(pages[i]));
845 }
846 return 0;
847 }
848
849 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
850 size_t count, loff_t *ppos)
851 {
852 loff_t pos;
853 loff_t start_pos;
854 ssize_t num_written = 0;
855 ssize_t err = 0;
856 int ret = 0;
857 struct inode *inode = fdentry(file)->d_inode;
858 struct btrfs_root *root = BTRFS_I(inode)->root;
859 struct page **pages = NULL;
860 int nrptrs;
861 struct page *pinned[2];
862 unsigned long first_index;
863 unsigned long last_index;
864
865 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
866 PAGE_CACHE_SIZE / (sizeof(struct page *)));
867 pinned[0] = NULL;
868 pinned[1] = NULL;
869
870 pos = *ppos;
871 start_pos = pos;
872
873 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
874 current->backing_dev_info = inode->i_mapping->backing_dev_info;
875 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
876 if (err)
877 goto out_nolock;
878 if (count == 0)
879 goto out_nolock;
880 #ifdef REMOVE_SUID_PATH
881 err = remove_suid(&file->f_path);
882 #else
883 # if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
884 err = file_remove_suid(file);
885 # else
886 err = remove_suid(fdentry(file));
887 # endif
888 #endif
889 if (err)
890 goto out_nolock;
891 file_update_time(file);
892
893 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
894
895 mutex_lock(&inode->i_mutex);
896 first_index = pos >> PAGE_CACHE_SHIFT;
897 last_index = (pos + count) >> PAGE_CACHE_SHIFT;
898
899 /*
900 * if this is a nodatasum mount, force summing off for the inode
901 * all the time. That way a later mount with summing on won't
902 * get confused
903 */
904 if (btrfs_test_opt(root, NODATASUM))
905 btrfs_set_flag(inode, NODATASUM);
906
907 /*
908 * there are lots of better ways to do this, but this code
909 * makes sure the first and last page in the file range are
910 * up to date and ready for cow
911 */
912 if ((pos & (PAGE_CACHE_SIZE - 1))) {
913 pinned[0] = grab_cache_page(inode->i_mapping, first_index);
914 if (!PageUptodate(pinned[0])) {
915 ret = btrfs_readpage(NULL, pinned[0]);
916 BUG_ON(ret);
917 wait_on_page_locked(pinned[0]);
918 } else {
919 unlock_page(pinned[0]);
920 }
921 }
922 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
923 pinned[1] = grab_cache_page(inode->i_mapping, last_index);
924 if (!PageUptodate(pinned[1])) {
925 ret = btrfs_readpage(NULL, pinned[1]);
926 BUG_ON(ret);
927 wait_on_page_locked(pinned[1]);
928 } else {
929 unlock_page(pinned[1]);
930 }
931 }
932
933 while(count > 0) {
934 size_t offset = pos & (PAGE_CACHE_SIZE - 1);
935 size_t write_bytes = min(count, nrptrs *
936 (size_t)PAGE_CACHE_SIZE -
937 offset);
938 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
939 PAGE_CACHE_SHIFT;
940
941 WARN_ON(num_pages > nrptrs);
942 memset(pages, 0, sizeof(pages));
943
944 ret = btrfs_check_free_space(root, write_bytes, 0);
945 if (ret)
946 goto out;
947
948 ret = prepare_pages(root, file, pages, num_pages,
949 pos, first_index, last_index,
950 write_bytes);
951 if (ret)
952 goto out;
953
954 ret = btrfs_copy_from_user(pos, num_pages,
955 write_bytes, pages, buf);
956 if (ret) {
957 btrfs_drop_pages(pages, num_pages);
958 goto out;
959 }
960
961 ret = dirty_and_release_pages(NULL, root, file, pages,
962 num_pages, pos, write_bytes);
963 btrfs_drop_pages(pages, num_pages);
964 if (ret)
965 goto out;
966
967 buf += write_bytes;
968 count -= write_bytes;
969 pos += write_bytes;
970 num_written += write_bytes;
971
972 balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);
973 if (num_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
974 btrfs_btree_balance_dirty(root, 1);
975 btrfs_throttle(root);
976 cond_resched();
977 }
978 out:
979 mutex_unlock(&inode->i_mutex);
980
981 out_nolock:
982 kfree(pages);
983 if (pinned[0])
984 page_cache_release(pinned[0]);
985 if (pinned[1])
986 page_cache_release(pinned[1]);
987 *ppos = pos;
988
989 if (num_written > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
990 err = sync_page_range(inode, inode->i_mapping,
991 start_pos, num_written);
992 if (err < 0)
993 num_written = err;
994 } else if (num_written > 0 && (file->f_flags & O_DIRECT)) {
995 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
996 do_sync_file_range(file, start_pos,
997 start_pos + num_written - 1,
998 SYNC_FILE_RANGE_WRITE |
999 SYNC_FILE_RANGE_WAIT_AFTER);
1000 #else
1001 do_sync_mapping_range(inode->i_mapping, start_pos,
1002 start_pos + num_written - 1,
1003 SYNC_FILE_RANGE_WRITE |
1004 SYNC_FILE_RANGE_WAIT_AFTER);
1005 #endif
1006 invalidate_mapping_pages(inode->i_mapping,
1007 start_pos >> PAGE_CACHE_SHIFT,
1008 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
1009 }
1010 current->backing_dev_info = NULL;
1011 return num_written ? num_written : err;
1012 }
1013
1014 int btrfs_release_file(struct inode * inode, struct file * filp)
1015 {
1016 if (filp->private_data)
1017 btrfs_ioctl_trans_end(filp);
1018 return 0;
1019 }
1020
1021 static int btrfs_sync_file(struct file *file,
1022 struct dentry *dentry, int datasync)
1023 {
1024 struct inode *inode = dentry->d_inode;
1025 struct btrfs_root *root = BTRFS_I(inode)->root;
1026 int ret = 0;
1027 struct btrfs_trans_handle *trans;
1028
1029 /*
1030 * check the transaction that last modified this inode
1031 * and see if its already been committed
1032 */
1033 if (!BTRFS_I(inode)->last_trans)
1034 goto out;
1035
1036 mutex_lock(&root->fs_info->trans_mutex);
1037 if (BTRFS_I(inode)->last_trans <=
1038 root->fs_info->last_trans_committed) {
1039 BTRFS_I(inode)->last_trans = 0;
1040 mutex_unlock(&root->fs_info->trans_mutex);
1041 goto out;
1042 }
1043 mutex_unlock(&root->fs_info->trans_mutex);
1044
1045 /*
1046 * ok we haven't committed the transaction yet, lets do a commit
1047 */
1048 if (file->private_data)
1049 btrfs_ioctl_trans_end(file);
1050
1051 trans = btrfs_start_transaction(root, 1);
1052 if (!trans) {
1053 ret = -ENOMEM;
1054 goto out;
1055 }
1056 ret = btrfs_commit_transaction(trans, root);
1057 out:
1058 return ret > 0 ? EIO : ret;
1059 }
1060
1061 static struct vm_operations_struct btrfs_file_vm_ops = {
1062 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
1063 .nopage = filemap_nopage,
1064 .populate = filemap_populate,
1065 #else
1066 .fault = filemap_fault,
1067 #endif
1068 .page_mkwrite = btrfs_page_mkwrite,
1069 };
1070
1071 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
1072 {
1073 vma->vm_ops = &btrfs_file_vm_ops;
1074 file_accessed(filp);
1075 return 0;
1076 }
1077
1078 struct file_operations btrfs_file_operations = {
1079 .llseek = generic_file_llseek,
1080 .read = do_sync_read,
1081 .aio_read = generic_file_aio_read,
1082 .splice_read = generic_file_splice_read,
1083 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
1084 .sendfile = generic_file_sendfile,
1085 #endif
1086 .write = btrfs_file_write,
1087 .mmap = btrfs_file_mmap,
1088 .open = generic_file_open,
1089 .release = btrfs_release_file,
1090 .fsync = btrfs_sync_file,
1091 .unlocked_ioctl = btrfs_ioctl,
1092 #ifdef CONFIG_COMPAT
1093 .compat_ioctl = btrfs_ioctl,
1094 #endif
1095 };
Linux kernel - Deliverables
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